Auto merge of #14631 - ConnorGBrewster:datetime_fix, r=Ms2ger

Make datetime just reflect

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This just uses `make_getter!` for `datetime` rather than checking if `datetime` has data and falling back to the child data if `datetime` has no data.

I reverted 2 of the test changes and added back an old test that makes sure that child content is not returned when `datetime` is empty.

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- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix #14611 (github issue number if applicable).

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- [ ] These changes do not require tests because _____

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